Fusible plug.



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UNITED STATES PATENT Enron.

CHARLES G. PERKINS, OE HARTFORD, CONNECTICUT, ASSIGNOR TO THE PERKINS ELECTRIC SWITCH MANUFACTURING COMPANY, OF SAME PLACE.

FUSIBLE PLUG.

SPECIFICATION forming part of Letters Patent No. 637,891, dated November 28, 1899.

Application led June 30, 1899.

To all whom t may concern:

Be it known that I, CHARLES G. PERKINS, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Fusible Plugs, of which the following is a specilication.

This invention relates to those plugs which are employed for temporarily connecting electric branch Wires--such as lead to and from fans, lamps, heaters, and similar electrical apparatus-with sockets that are connected with electric line-wires.

The object of this invention is to provide a fusible plug that will be cheap to lnanufacture, that will be simple to manipulate, that will be safe to handle, and that will be sure in an emergency.

The plug that is illustrated in the accompanying drawings as embodying the invention has a body of insulating material provided with means for attachment to and contact with the terminals of a common socket and provided with insulated fingers for the attachment of the cap and a cap of insulating material provided with plates and binding-screws for the connection of the branch wires and provided with arms and clampingscrews that cooperate with the fingers on the body for fastening the body and cap together, the plates and their binding-screws being separated from the arms and their clampingscrews by walls of insulating material and each arm being connected with a plate by a fusible wire that extends from one to the other over a wall of insulating material.

Figure l of the drawings shows a side View, on enlarged scale, of this plug` with the body and cap separated in order to better show the means provided for fastening them together. Fig. 2 is a central section taken through the body and the cap fastened together. Fig. 3 is a view looking into the body, and Fig. e is a view looking into the cap.

The body l of the plug shown, which is preferably formed of porcelain, is provided with the usual threaded sleeve 2 necessary for attachment to and connection with the threaded sleeve of a socket of the so-called Edison type. This sleeve is, by a screw 3, connected with a plate et, located in the bottom seau no. 722,413. dit maar.)

of the recess in the body. The plate t is bont outwardly, and the outer end is shaped so as to form iingers 5, that are a little thicker near their outer ends than they are farther in from their outer ends. A screw 6 extends through the center of the body and joins the washer 7, that is arranged to make contact with the central terminal of the socket, with a plate that is located in the bottom of the recess in the body and that has an outwardly-extending part formed with ilngers 9 similar to the fingers 5, projecting from the plate 4. These plates At and S are located in the recess in the body, so that the fingers 5 and 9 will be reinforced by solid walls 22, of insulation, and so that the opening between the `fingers may be reached from the exterior through openings lO in the walls of the body around the recess. A disk, of mica, ll is placed in the bottom of the recess in the body outside of the platest and 8 after they have been secured in position, and as these plates are sunk in the insulation and the mica lies flat against the bottom of the recess one plate is completely insulated from the other.

The cap l2 is preferably a disk of porcelain, with a central perforation 13 for the entrance of the wires. The ends of the wires are fastened by binding-screws 14 to the conductingplates l5, that are secured to the inside face of the cap upon opposite sides of the central perforation. Arms 1G are secured to theinner face of the cap, and in threaded perforations through these arms turn clamping-screws 17. The screws have bevel-heads, and the arms are placed such a distance apart that they will just fit inside of the fingers, with the heads of the screws extending through the openings between the iingers when the body and cap are placed together. The arms and clamping-screws are separated from the plates and binding-screws by walls 18, of insulating material, that extend outwardly from the face of the cap nearly to the bottom of the recess in the body, so that when the parts are put together the plates are practically shut within a recess insulated from the arms. Afusewire 19 is led from the binding-screw 2O of each plate over an ins ulating-wall and joined to an arm by a binding-screw 2l, thus putting a fuse in each side of the circuit. The branch wires are passed through the perforation in the cap and the end of each attached to a binding-plate, each binding-plate being connected by a fusible wire with an attachingarm, from which it is separated by insulating material. The cap is then placed over the end of the body, with the attaching-arms on the cap passing inside of the fingers on the body and the fastening-screws extending through the openings between the fingers.

When these screws are tightened up, the bevelheads pass into the larger parts of t-he openings between the fingers. rthe diameters of the bevel portions of the heads that pass between the fingers are greater than the distance between the fingers near their ends, where they are thicker, so that the heads of the screws cannot be pulled out of the openings between the fingers unless the fingers separate; but as the fingers are backed by walls of insulation they cannot be spread apart. By loosening the attaching-screws the cap and body may be separated, for the shanks of the screws are small enough to pass through the narrowest parts of the openings between the fingers. A slight loosening of the screws, however, will not permit the separation of the body and the cap. There must be a substantial loosening, so that the entire head is turned out of the openings between the fingers.

The device embodying the present invention is a double-pole plug in that there are double terminals-a set for each side of the circuit and a fuse for each side of the circuit. The body and cap are formed of insulating material and can be quickly put together, and when secured they cannot accidentally be pulled apart, although they may be easily separated, if desired, for renewing the fuse-wires. The fuse-wires are se separated from the other conducting` parts by insulating material that should they blow out an arc would not be established inside of the plug. The body of the plug maybe provided with means for attaching it to any of the common types of sockets.

l claim as my inventionl. A fuse-plug consisting of an insulatingbody having a conducting-shell for attaching the body to a socket, a conducting-plate for engagement with a conducting part of the socket, and conducting means connected with the shell and with the plate for the attachment of the cap, and a cap having two insulated conducting-plates with binding-screws for the attachment of the branch wires, and insulated conducting means for attaching the cap to the body with two fuse-wires, one conest/,sei

necting each plate with each attachment means in the cap, substantially as specified.

2. A fuse-plug consisting of an insulatingbody having conducting means for attaching the body to a socket, and conducting-fingers projecting longitudinally of the body for the attachment of the cap, one of said fingers being` connected with the body-attaching means, and an insulating-cap having two conductingplates with binding-screws for the connection of the branch wires, and two conducting-arms projecting longitudinally of thc cap for attachment to the fingers of the body, with a fuse-wire connecting each plate with each arm in the cap, substantially as specified.

3. A fuse-plug consisting of an insulatingbody having means for attaching the body to a socket and iingers for the attachment of the cap, and a cap having two plates with binding-screws for the connection of the branch wires, and two arms for attachment to the body, walls of insulating material separating the arms from the plates, with a fuse-wire passing over a wall of insulating material and connecting each plate with each arm, submstantially as specified.

4t. A fuse-plug consisting of an insulatingbody having means for attaching the body to a socket and metallic fingers for the attachment of the cap, said fingers being located in openings in insulating material Aso that they cannot be spread apart, and a cap having plates with binding-screws for the connection of the branch wires, metallic arms bearing screws havin g heads that are arranged to pass between the fingers for fastening the cap and body together, and Vfuse-wire connecting the plates and the arms,substantiall y as specified.

5. A fuse-plug consisting of an insulatingbody having means for attaching the body to a socket and metallic fingers with the openings between the fingers near the ends narrower than some distance back from the ends, said fingers beinglocated in openings in the insulating material so that they cannot be spread apart, and a cap having plates with bindingscrews for the connection ofthe branch wires, metallic arms bearing bevel-head screws that are arranged to pass between the fingers, the shanks of the screws being narrower than the openings between the fingers near their ends and the heads of the screws being wider than said openings, and fuse-wire connecting the plates and the arms, substantially as specified.

CHARLES G. PERKNS. iVitnesses:

H. R. WILLIAMS, C. E. BUCKLAND.

ITO 

